27/05/2026
🪫 MINI Countryman Hybrid with poor electric range…. Can we fix it? 🪫
This MINI Countryman F60 Hybrid arrived at Burch Motor Works with a frustrating intermittent hybrid system fault and almost no usable EV range. The owner reported the vehicle would sometimes fail to fully charge, regularly displaying hybrid system warning messages and only achieving around 6 miles of electric range before dropping out.
We began by carrying out a full vehicle diagnostic test, which immediately revealed several high voltage battery faults stored within the system. Faults were present for battery shutdown events, overvoltage monitoring within the cell supervision circuits, along with an unrelated automatic transmission coding fault.
From there, we moved onto detailed live data analysis of the high voltage battery system. Initial readings showed the battery would only accept a maximum charge of around 52–53%, which already suggested the HV battery capacity had significantly deteriorated.
Digging deeper into the individual battery cell readings, we found cells 6 and 9 within battery module 1 were noticeably lower than the others, with another slightly weaker cell also identified in module 2. To confirm the issue, the vehicle was left powered up in the workshop to naturally discharge the battery further while we monitored the live voltages.
As the charge level dropped, the suspect cells began falling away from the others much faster — a clear sign of internal battery deterioration and imbalance within the module.
We then placed the vehicle on charge overnight and rechecked the data the following morning. The battery had balanced itself slightly during charging, with all modules sitting closer together at around 4.1 volts per cell, however the vehicle still only displayed around 8 miles of EV range.
The next stage was road testing whilst monitoring the individual battery modules live. During driving, the weaker cells within module 1 again dropped significantly faster than the remaining cells. After only around 2 miles of driving, the EV range had already fallen to zero, with the usable battery charge dropping from 53% down to 26% in an extremely short distance.
This confirmed the HV battery was no longer capable of delivering reliable usable range, with module 1 excessively worn and likely suffering from aged battery cell deterioration.
After discussing the options with the customer, the most cost-effective and sensible repair route was to replace the complete high voltage battery assembly with a reliably sourced used unit.
Once installed, the replacement HV battery was fully programmed, matching the new cell codes to the SME, charged and then cycled through multiple charge and discharge procedures to allow the battery management system to relearn and balance correctly.
The result was a huge improvement, with the MINI now achieving an average of around 14 miles of stable electric driving range and operating exactly as it should once again.
Of course this range seems small, however it is a small battery in this vehicle and normal use of the petrol engine fitted makes this a practical car to use either sources of drive!
Another hybrid EV repaired successfully.⚡🔋🔧
🔋 Burch Motor Works 🔋
Proud members of HEVRA - Hybrid and Electric Vehicle Repair Alliance
www.burchmotorworks.co.uk/services/hybrid-electric-vehicle-maintenance-servicing/
